This guide is primarily concerned with outdoor ac substations, either conventional or
gas-insulated. These include distribution, transmission, and generating plant substations. With
proper caution, the methods described herein are also applicable to indoor portions of such
substations, or to substations that are wholly indoors. No attempt is made to cover the grounding
problems peculiar to dc substations. A quantitative analysis of the effects of lightning surges is
also beyond the scope of this guide. (Incorporates IEEE Std P80-2013/Cor 1-2015)

This guide is primarily concerned with outdoor ac substations, either air-insulated or gas-insulated. With proper caution, the methods described herein are applicable to indoor portions of such substations, or to substations that are wholly indoors.
No attempt is made to cover the grounding problems peculiar to dc substations. A quantitative analysis of the effects of lightning surges is also beyond the scope of this guide.